diff --git a/ChangeLog b/ChangeLog
index e01136c6eb..4111d742c0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2018-05-24  Gabriel F. T. Gomes  <gabriel@inconstante.eti.br>
+
+	[BZ #23171]
+	* math/math.h [C++] (iseqsig): Fix parameter type for the long
+	double version.
+
 2018-05-23  Joseph Myers  <joseph@codesourcery.com>
 
 	* sysdeps/sh/Implies: Remove sh/soft-fp.
diff --git a/math/math.h b/math/math.h
index 87240336e0..ddee4e4083 100644
--- a/math/math.h
+++ b/math/math.h
@@ -1511,7 +1511,7 @@ template<> struct __iseqsig_type<double>
 
 template<> struct __iseqsig_type<long double>
 {
-  static int __call (double __x, double __y) throw ()
+  static int __call (long double __x, long double __y) throw ()
   {
 #  ifndef __NO_LONG_DOUBLE_MATH
     return __iseqsigl (__x, __y);